In 1981 a detergent was sold on the European market with an enzymatic additive comprising a mixture of ALCALASE.RTM. and ESPERASE.RTM., i.e. two alkaline proteases from Bacillus sp.
Also, it appears from Osaka Shiritsu Daigaku Seikatsu Kagakubu Kiyo 23, (1975), page 69, that in a washing process it is sometimes more effective to use a mixture of a neutral protease and an alkaline protease. No data or further details of the combined effect are provided.
Also, U.S. Pat. No. 4,511,490 describes a cooperative mixture of two proteases. The exemplified proteases are all alkaline proteases from Bacillus sp. The effect is only demonstrated by measuring hydrolysis of a casein solution in the absence of detergent. It is speculated that the protease combination may provide improved detergency, but data from washing tests are not provided. The highest activity was found at a mixing ratio of the two proteases on activity basis from approx. 1:2 to approx. 2:1.
Further, Japanese examined patent application publication 61-19,679 describes the use in a detergent of a combination of two proteases. The exemplified combination uses alkaline proteases from Bacillus sp. The data from washing tests do not show any improved detergency over the use of a single protease, but merely that the effect extends over a broader temperature range than that of each protease alone. The mixing ratio of the two proteases is 1:1 on activity basis.
Thus, a detergent additive comprising two alkaline proteases from Bacillus sp. for detergents is known, but data showing improved detergency have not been published. Examples later in this specification demonstrate that, in fact, the detergency of such mixtures is only slightly better than that of the single proteases. Detergent additive comprising an alkaline bacterial protease together with an alkaline fungal or actinomycete protease has not previously been described.
The use of alkaline bacterial and fungal proteases together for treatment of leather is disclosed in West German patent publications DE-2,301,591A, DE-2,307,603A, DE-2,308,967A and DE-2,321,629A. The effects obtained therein are unhairing, bating and softening of leather, and the chemical environment includes reducing sulfur compounds; such as sulfide, mercaptans or sulfite, but does not include surfactant or other common detergent components.